Answer:
actual efficiency is  47.78 %
Carnot efficiency  is 67.65 %
power output is 5.20 × 10^3 hp
Explanation:
given data 
temperature = 1900°C = 1900+ 273 K = 2173 K
exhaust temperature = 430°C = 430 + 273 K = 703 K
fuel = 7.0 × 10^9 cal 
work = 1.4 × 10^10 J 
to find out 
actual efficiency  and Carnot efficiency and power output of engine
solution
first we find actual efficiency that is = work / heat input
put the value and
input energy  = 7.0 × 10^9 cal  (4.184 J/1 cal)  = 29.29 × 10^9 J
actual efficiency  =  1.4 × 10^10 / ( 29.29 × 10^9 )
actual efficiency  =  0.4778 
actual efficiency is  47.78 %
and
Carnot efficiency  is = 1 - ( 703 / 2173 ) 
so Carnot efficiency  is  = 0.67648
Carnot efficiency  is 67.65 %
and
power output  = work / time
power output  =  1.4 × 10^10 / 3600 sec
power output = 3.88 × 10^6 W
power output = 3.88 × 10^6 W / 746 hp 
so power output is 5.20 × 10^3 hp